Besides, in further testing I left the x3 some time on and after a couple of minutes it gets the same blank screen. If I keep powering it on, it gets that blank sooner and sooner, and if i leave it some time to rest it takes longer.

So Im guessing some power issues and/or maybe with condensers ?? Along with the connections ...

Is there any schematic so I can try to fix this ? Maybe measure V in some points ...

Having it repaired in the official tec i assume it would cost more than just buying a used replacement unit plus havent found any in my country